The present invention relates to a crane system that incorporates a continual conveyor system for moving discrete items of freight, in particular sacks, crates, bundles, or the like, comprising at least one vertical conveyor section adjoining other conveyor sections that have horizontal or close to horizontal conveyor lines, said at least one vertical conveyor section being rotatable about a vertical axis in a traversing housing, there being a horizontally arranged circular conveyor at least at one end of the vertical conveyor.
Known mobile ship unloading systems, such as are described, for example, in DE-OS 29 32 113 or in DE-OS 30 29 863, incorporate vertical conveyors that are suspended from the crane, and incorporate an L-shaped pick-up arm for bulk material. The vertical conveyor is configured as a grater or bucket belt and moves the bulk material from the pick-up in the ship to a circular conveyor that is incorporated ahead of the conveyor belt of the boom. This transfer of the bulk material in the upper area of the vertical conveyor is effected by dropping it into a conveyor chute and then onto the circular conveyor. From there, when the bulk material is removed, as is made clear in DE-AS 24 56 260, by rotating carrier shovels that feed the bulk material to a base opening in the stationary trough of the circular conveyor.
A similar distribution system of bulk material is known from DE-OS 24 47 600, wherein a traversable vertical conveyor discharges the bulk material via an inclined trough to a rotating circular conveyor. The removal of the bulk material from the circular conveyor onto a conveyor belt is, in this case, effected by means of a clearing wheel, the clearing arms of which fit into the trough of the circular conveyor.
All of the systems described heretofore are suitable only for conveying bulk materials along the unloading direction, with bulk materials being dropped from the vertical conveyors and then moved further on by means of troughs or chutes. Were these systems used to move discrete items of freight, such as sacks or cases, this would cause very severe damage during the transfer from the vertical conveyor to the circular conveyor because of the drop into the chutes. In addition, it is impossible to reverse the direction of movement so as to load a ship using such systems, since all of the system operate only as unloading systems.
DE-AS 12 74 505 proposes that for purposes of loading individual items of freight, the freight be moved to the vertical conveyor at equal time intervals by means of timed or pulse-type belts. However, the system described therein permits only the loading of ships and does not permit the loading station to be traversed within the ship.